The present invention relates to a communications system, a communications apparatus, and a communication method and, in particular, to a communications system, a communications apparatus, and a communication method that solve a problem caused by storing critical information on a card.
A system that allows a user to purchase goods using a credit card, a debit card, or a card having an electronic money capability is one of settlement systems that trade (settle) an electronic value having the same value as money (hereinafter also simply referred to as a value).
In a card settlement system, a user (customer) carries a card on a daily basis. When trading the value, in some system, a terminal installed in a store reads data stored on the user's card. The readout data is transmitted to a card provider via a network dedicated to the card provider to trade the value. In another system, card information input from a terminal, such as user's cell phone or a personal computer, is transmitted to a card provider via a public network including the Internet to trade the value (refer to, for example, Japanese Unexamined Patent Application Publication No. 2002-183443 and Japanese Unexamined Patent Application Publication No. 2001-175751).
Accordingly, the card contains critical information including information such as a private key for identifying (authenticating) the card (i.e., the user who holds the card) and information about a value that the user currently holds. The card provider verifies the authenticity of the card from the critical information stored on the card and information input by the user, and subsequently, carries out transfer of the value (i.e., settlement).
However, since critical information is stored on a card and the card is carried by a user, there is a possibility that the user could lose the card and the critical information stored on the card leaks. Also, there is a possibility that the critical information stored on the card could be skimmed.